Final answer:
In complementation tests, homozygous recessive crosses like aa x aa do not result in complementation, while crosses of different loci like aaBB x AAbb will. Test crosses like AaBb x aabb can yield parental and recombinant types, depnding on linkage. Monohybrid crosses follow Mendelian ratios.
Step-by-step explanation:
In complementation tests, if the test crosses are between organisms recessive for mutations at the same locus (i.e., homozygous recessive organisms such as aa cross with aa), we expect that no complementation will occur as both organisms carry mutations in the same gene, resulting in the same mutant phenotype. On the other hand, if the test crosses involve organisms that are recessive at different loci (e.g., aaBB cross with AAbb), complementation will occur, and the progeny will exhibit the wild-type phenotype since each parent provides a functional allele for the other's mutated gene.
During a test cross such as AaBb x aabb, the expected outcomes depend on whether the genes are linked or unlinked. With linked genes, the majority of offspring are expected to have parental type combinations like AaBb or aabb, but some offspring will display recombination phenotypes (e.g., Aabb or aaBb). However, if genes are unlinked, assorting independently, progeny will have combinations with equal frequency, showing all possible allele combinations according to Mendel's independent assortment. In another cross scenario involving a monohybrid cross, when we cross two organisms with Aa genotype, the Mendelian genotype ratio is expected to be 1:2:1 (AA:Aa:aa) and the phenotype ratio for dominant to recessive is expected to be 3:1, if a simple dominant-recessive relationship exists between alleles.